x64 not showing all 4GB

[emorrp1]

read this for a full, easy-to-read explanation: http://www.dansdata.com/askdan00015.htm
However there may be something more here, as I was under the impression that Linux did the re-allocate above method.

[DrHu]

http://www.cyberciti.biz/faq/ubuntu-lin ... -solution/

Option # 1: Use 64 bit Ubuntu Linux

64 bit Linux kernel will take care of 4G or more memory. Just grab latest 64 bit version and install it.
Option #2: Install PAE enabled kernel

Open terminal and type the following command:
$ sudo apt-get update
$ sudo sudo apt-get install linux-headers-server linux-image-server linux-server

Mint..pae??
http://forums.linuxmint.com/viewtopic.php?f=49&t=22706
http://forums.linuxmint.com/viewtopic.php?f=49&t=27775
http://forums.whirlpool.net.au/forum-re ... 52911.html

4) PAE itself (the technology that enables a 32-bit OS to address up to 64 GB of RAM), slows down memory addressing and memory referencing. That is why PAE is disabled by default on my kernels.

Summary: It is not best to use the Ubuntu Server kernel on desktop systems. Sure, it works, but not optimally. If you want to use the a 32-bit Ubuntu, you are much better off recompiling your own kernel with PAE enabled, than to use the Ubuntu Server kernel.

Of course, considering that using the AMD64 port will also give you about 10%-15% speed boost, you are missing on a lot of performance by using the 32-bit Ubuntu Server kernel on a 64-bit capable CPU.

posted by aryonoco (#225791)

[richyrich]

Hi Iterator,
No, I think DrHu didn't read your post, or is trying to confuse you. How much shared vga memory do you have allocated?

regards, Richard

ps: If you read the second half of the link emorrp1 gave you (below the Windows memory pic), there is a much better explanation.

EDIT: spelling!

[richyrich]

You may want to check your Manufacturers website, I've seen some that take up anywhere from 64Mb to 1.5Gb of reserved space!

[Fred]

Iterator,

If in fact you did install the 64 bit system, your kernel should be correct. You didn't change it did you? So that is probably not the issue.

I would suggest you check your motherboard against the manufacturers specifications to determine if it will operate in 64 bit mode. Believe it or not, a lot of the first so-called 64 bit motherboards would run 64 bit CPUs and OSs, but only in 32 bit mode.

I know, it sounds unreasonable, but it is true none-the-less.

If this is the case, then you are getting the memory availability that I would expect. In a 32 bit system, up to 1 Gig of the 4 Gig address space is reserved for hardware and other system purposes.

Fred

[subslug]

I guess this doesn't really prove anything but I have 4Gb of ram on my 64 bit install and it's showing 3.8Gb



I don't really know why yours is reading so much less? My system does have built in video but, I'm not using it and instead have an add on card.

[Fred]

subslug,

In your case, it wouldn't surprise me if some of your RAM is being reserved for your on-board video, even though you aren't using it. If I were you I would look closely at your BIOS settings for a way to disable possible video caching.

In Iterator's case I suspect his hardware isn't capable of running in 64 bit mode and is automatically falling back to 32 bit addressing.

Fred